Flag should fly at half-mast on Australia Day: Indigenous MP

AN INDIGENOUS MP says flags should be flown at half-mast across the state on Australia Day amid a new campaign to dump the divisive public holiday.

Lidia Thorpe - the first Aboriginal woman in Victoria's Parliament after winning the Northcote by-election last year - told the Herald Sun Australia Day celebrations were akin to dancing on the graves of her ancestors.

A fresh push to change the date of Australia Day has even won the backing of Wimbledon hero Pat Cash - who said today the treatment of indigenous Australian meant he could no longer celebrate the day.

The former tennis champ said "real Australians" would not be celebrating Australia Day.

"I'm not celebrating the day the British landed here and started butchering the Aboriginal people," Cash told 3AW.

Former PM Tony Abbott and Nationals leader Barnaby Joyce have slammed the Greens for their "politically correct" stance.

Prime Minister Malcolm Turnbull said yesterday a free country should debate its history, not deny it.

"Australia Day is Australia's day - a day when we come together and celebrate our nation and all of its history," he said.

Ms Thorpe said her people were being "disrespected" on January 26

"We can't celebrate a day that marks a day of invasion, a day of mourning," she said.

"This country needs to own the truth of what's happened to its first people. We need to own that we were invaded and atrocities occurred."

Indigenous MP Lidia Thorpe says January 26 is a day of mourning. Picture: Aaron Francis/The Australian

Along with lowering the flag and not celebrating the day, Ms Thorpe has also called for a treaty to be negotiated and a new day agreed upon that represents all Australians.

Her call comes after federal Greens Leader Richard Di Natale flagged changing the day as a key focus for the year.

Senator Di Natale has told more than 100 local Greens councillors to take action at a local government level.

At least three Melbourne councils have already dumped Australia Day celebrations, including Darebin, Moreland and Yarra.

The issue will also likely loom large in an election year with the Greens set target Labor with a "Change the Date" campaign.

A potential by-election for the federal seat of Batman would likely be fertile ground for the issue, along with inner city seats of Brunswick and Richmond in the looming state election in November.

An Andrews Government spokesman acknowledged Victorians had differing views on the issue.

"This date means many different things to different people, and that for Aboriginal people in particular the 26th of January is a difficult day," he said.

"But the Government believes that we get the balance right - we respect the traditional owners of our land, but we then get on and celebrate in a really unified way."

State Opposition Leader Matthew Guy said the Coalition supported the historical day.

"Australia Day is January 26 - a vote for the Liberals and Nationals is a vote to keep that date."